Various abbreviations found in the specification are defined as follows:
3GPP third generation partnership project
LTE long term evolution
OFDMA orthogonal frequency division multiple access
UTRA universal territory radio access
UE user equipment
Node-B base station
eNB evolved Node-B
DL downlink (Node B to UE)
UL uplink (UE to Node B)
MCS modulation and coding scheme
SC-FDMA single carrier, frequency division multiple access
CCH control channel
CRC cyclic redundancy check
MBMS multimedia broadcast and multicast service
A proposed communication system known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as 3.9G/LTE) is currently under discussion within the 3GPP. The current working assumption is that the DL access technique will be OFDMA, and the UL technique will be SC-FDMA.
Currently, a control channel concept for separately coding the resource allocation signaling is under discussion. At a 3GPP RAN1 meeting (RAN1#47, Riga, Nov. 6-10, 2006) it was decided to use the following assumptions for the control channel for DL control signaling (see TSG-RAN WG1 #47, R1-063580, “Way forward on downlink L1/L2 control signaling”):
downlink control signaling is located in the first n OFDM symbols of a sub-frame;
n<3;
data transmission in the downlink can, at the earliest, begin at the same OFDM symbol as the control signaling ends;
multiple control channels are used;
each control channel is convolutionally coded;
a UE monitors a number of control channels;
one control channel carries information for one MAC ID;
at least two formats (MCS) for control signaling is supported; and
the power setting of each control channel is determined by the Node-B.
Reference may also be had, for example, to TSG-RAN WG1 #47, R1-063147, “Downlink L1/L2 control signaling”.
Further, in LTE the multiplexing of MBMS may occur in several different ways. IN one technique unicast services (normal cellular operation) and MBMS are multiplexed in the time domain (TDM). The MBMS transmissions are such that the content is the same in multiple cells. That means that there would be certain sub-frames where there would be no cell-specific shared DL channel. Most of the DL resources in the sub-frame would be used to transmit MBMS data common to many cells. There would, however, be a cell-specific control channel transmitted even in MBMS sub-frames, and this control channel would possibly signal UL assignments and Ack/Nacks for UL transmission. For this reason, it is possible that cell-specific control channels in MBMS sub-frames may be smaller than in unicast sub-frames.
Of particular interest to the exemplary embodiments of this invention that are described below is the encoding structure of the control channel.